last index of
finds the last occurrence of a substring in a string
(string subject, string search, long end) -> long
search at or before index
end, returns the index of the last such occurrence. Returns
nil, it is interpreted as the last index of
|string||The string to search in|
|string||The string to find|
The index of the last character where search should begin.
Indexes are zero-based, i.e. the first character is at index 0.